The compounds 1-hydroxy-2-isovaleryl-4,4,6,6-tetramethyl cyclohexen-3,5-dione and 1-hydroxy-2-isobutyrl-4,4,6,6-tetramethyl cyclohexen-3,5-dione having the structural formulae ##STR2## respectively have been isolated from the plant family Myrtaceae, plant genus Leptospermum and Xanthostemon and are described in the literature (R. O. Hellyer, Aust. J. Chem., 21, 2825 (1968) but no utility therein is taught.
Also, the compound 1-hydroxy-2-acetyl-4,4,6,6-tetramethyl cyclohexen-3,5-dione having the structural formula ##STR3## is known but no utility for the compound is taught (A. C. Jain and T. R. Seshadri, Proc. Indian Acad. Sci. 42A, 279-84 (1955)).